Main FeaturesControlled by built-in overlapped or parallel-connected electromagnetic precursor valve, with advanced craft and reliable action;Diaphragm of main valve adopts imported special rubber, with high anti-corrosion and resisting low temperature at -40° C;Special stainless steel magnetic material never rust or generate remanent magnetism;Close the main valve when the working pressure is 0.3-0.4MPa, and the small flow system will be 3-3.5L/min, which can be designed according to users' requirements.